JP2002322328A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition excellent in processability which has a low permanent compression set when highly expanded and a reduced mechanical strength deterioration. SOLUTION: The rubber composition contains (A) an ethylenic copolymer consisting of ethylene, an α-olefin with 3-20C and a non-conjugated polyene wherein the molar ratio(ethylene/α-olefin) is 40/60-93/7 and the non-conjugated polyene has an iodine value of 10-40, (B) a crystalline resin having a melting point (Tm) below 140 deg.C determined by a DSC(differential scanning calorimeter) and (C) an amorphous resin. The component ratio of the ethylenic copolymer (A), the crystalline resin (B) and the amorphous resin (C) are 100 pts.wt., 3-30 pts.wt., and 3-35 pts.wt., respectively while the sum of (B) and (C) remains in the range of 6-40 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition, and more particularly to a rubber composition having a low specific gravity, excellent balance between mechanical strength and compression set when foamed, and excellent workability. .

[0002]

2. Description of the Related Art Conventionally, ethylene / α-olefin / non-conjugated diene copolymers are excellent in weather resistance, heat resistance, cold resistance, ozone resistance, etc., and are used as building materials, automobile parts, electric wire coating materials and the like. Widely used. In particular, many rubbers mainly composed of EPDM are used around doors and trunk rooms in order to impart soundproofness and waterproofness inside and outside an automobile. In recent years, however, there has been an increasing need for weight reduction and cost reduction of automotive materials due to environmental problems. If the specific gravity of sponge materials is reduced in conventional EPDM, physical properties such as mechanical strength are greatly reduced. It is.

[0003] In recent years, the applicant of the present application has disclosed in
No. 0888, in EPDM, a rubber composition obtained by mixing LDPE and an ethylene-α-olefin copolymer having a melting point of 50 ° C. or more is used, whereby low expansion stress and compression of sponge rubber obtained by highly foaming are obtained. It is proposed that the permanent set is less reduced. However, in this system, further improvements in compression set are needed. In addition, WO97 / 0
No. 2316 discloses a rubber composition in which a crystalline polyolefin (polyethylene or polypropylene) resin is dispersed in a molten state in EPDM. However, the polyethylene-based resin needs to be improved in compression set as described above. In addition, polypropylene-based resins have satisfactory mechanical strength and compression set, but have poor workability when kneading a vulcanizing agent, and are not at a level that is sufficiently satisfactory from the balance between physical properties and workability. JP-A-2000-302904 proposes a rubber composition for a sponge in which a crystalline or amorphous synthetic resin (B) is blended with a rubber component (A) composed of EPDM. Is, as in the examples, polypropylene, polybutene-
It is a two-component system containing 1 or polystyrene, and is not at a level that is sufficiently satisfactory from the balance between physical properties such as modulus and mechanical strength and workability.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the compression set and the decrease in mechanical strength during high foaming by using an ethylene-based copolymer and a crystalline resin and an amorphous resin. An object of the present invention is to provide a rubber composition having excellent processability.

[0005]

According to the present invention, the following rubber composition is provided to achieve the above object of the present invention. (1) (A) It comprises ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene;
The molar ratio with the olefin (ethylene / α-olefin) is 40/60 to 93/7, and the non-conjugated polyene has an iodine value of 1
An ethylene copolymer in the range of 0 to 40, (B) DS
Melting point (Tm) measured by C (differential scanning calorimeter) is 14
A rubber composition containing a crystalline resin having a temperature of less than 0 ° C and an amorphous resin (C), wherein the proportion of the components (A) to (C) is
(A) 100 parts by weight of an ethylene copolymer, (B) 3 to 30 parts by weight of a crystalline resin, and (C) 3 to 3 parts by weight of an amorphous resin.
5 parts by weight, and the total amount of (B) the crystalline resin and (C) the amorphous resin is in the range of 6 to 40 parts by weight. (2) The rubber composition according to the above (1), wherein the (C) amorphous resin has a glass transition temperature (Tg) of 70 to 130 ° C. measured by DSC (differential scanning calorimeter). (3) In the rubber composition according to the above (1) or (2), (A) 100 parts by weight of the ethylene copolymer,
A rubber composition for a sponge, comprising 10 to 200 parts by weight of a filler, 0.3 to 20 parts by weight of a vulcanizing agent, and 1 to 10 parts by weight of a foaming agent. (4) A weather strip obtained by molding the rubber composition according to any one of (1) to (3).

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene copolymer (A) used in the rubber composition of the present invention is ethylene, having 3 carbon atoms.
And α-olefins having from 3 to 20 carbon atoms, which are composed of α-olefins of from 20 to 20 and non-conjugated polyene, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-
Decene and the like can be mentioned, and propylene, 1-butene, 1-hexene, 1-octene is preferably used, and propylene and 1-butene are more preferably used. These α-olefins can be used alone or in combination of two or more. The molar ratio of ethylene to α-olefin (ethylene / α-olefin) is 40/60 to 93 /
7, preferably in the range of 50/50 to 85/15,
More preferably, it is in the range of 60/40 to 80/20. When the molar ratio is within the above range, mechanical strength,
In addition, the compression set is preferably maintained in a well-balanced manner.

[0007] Non-conjugated polyenes include, for example,
5-ethylidene-2-norbornene, dicyclopentadiene, 5-propylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene,
Cyclic polyene such as 1,4-cyclohexadiene, 1,4-cyclooctadiene, 1,5-cyclooctadiene, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4 -Hexadiene, 5-methyl
-1,5-heptadiene, 6-methyl-1,5-heptadiene, 6-methyl-1,6-octadiene, 7-methyl-
1,6-octadiene, 5,7-dimethyl-1,6-octadiene, 7-methyl-1,7-nonadiene, 8-methyl-1,7-nonadiene, 8-methyl-1,8-decadiene, 9- Methyl-1,8-decadiene, 4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-octadiene, 7-methyl-4-ethylidene-1,6-nonadiene, 7-ethyl- 4-ethylidene-
Internal unsaturated bond having 6 to 15 carbon atoms, such as 1,6-nonadiene, 6,7-dimethyl-4-ethylidene-1,6-octadiene, and 6,7-dimethyl-4-ethylidene-1,6-nonadiene A chain polyene having 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene,
Α, ω-
A diene, and preferably 5-ethylidene-2-
Norbornene, dicyclopentadiene, 5-vinyl-2
-Norbornene, 7-methyl-1,6-octadiene,
Examples thereof include 5-methyl-1,4-hexadiene, and more preferably, 5-ethylidene-2-norbornene, dicyclopentadiene, and 5-vinyl-2-norbornene. These non-conjugated polyenes can be used alone or in combination of two or more. The non-conjugated polyene has an iodine value in the range of 10 to 40, preferably 2
It is in the range of 0-35. In this case, if the iodine value is less than 10, the mechanical strength is poor, while if it exceeds 40, the rubber elasticity is impaired.

The (A) ethylene copolymer has a Mooney viscosity (ML _{1 + 4,} 100 ° C.) in the range of 25 to 350, preferably 40 to 300. If the Mooney viscosity is less than 25, the mechanical strength of the obtained rubber vulcanizate tends to decrease, while if it exceeds 350, the processing properties of the obtained rubber composition are poor.

The ethylene copolymer (A) used in the present invention can be produced by an appropriate method such as a gas phase polymerization method, a solution polymerization method, and a slurry polymerization method. These polymerization operations can be carried out in a batch system or a continuous system. In the above solution polymerization method or slurry polymerization method, an inert hydrocarbon is usually used as a reaction medium. Such inert hydrocarbon solvents include, for example, n
Aliphatic hydrocarbons such as pentane, n-hexane, n-heptane, n-octane, n-decane, n-dodecane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; benzene, toluene, xylene and the like And aromatic hydrocarbons. These hydrocarbon solvents can be used alone or in combination of two or more. Further, the raw material monomer can be used as a hydrocarbon solvent.

As the polymerization catalyst used for producing the ethylene copolymer (A), for example, V, Ti, Z
An olefin polymerization catalyst comprising a compound of a transition metal selected from r and Hf and an organometallic compound can be exemplified. The transition metal compound and the organometallic compound,
Each can be used alone or in combination of two or more. Particularly preferred examples of such an olefin polymerization catalyst include a metallocene-based catalyst comprising a metallocene compound and an organoaluminum compound or an ionic compound which reacts with the metallocene compound to form an ionic complex, or a vanadium compound and an organoaluminum compound And a Ziegler-Natta catalyst.

[0011] The crystalline resin (B) used in the present invention comprises:
The melting point (Tm) measured by DSC is less than 140 ° C, preferably 70 ° C or more and less than 140 ° C, more preferably 90 ° C or less.
What is in the range of ~ 130 ° C is used. Specifically, ethylene homopolymer, LDPE, LLDPE, HD
Examples thereof include a polyethylene resin such as PE, and a 1,2-polybutadiene resin, and a polyethylene resin is preferably used. These crystalline resins (B) can be used alone or in combination of two or more. The crystalline resin (B) is used in a proportion of 3 to 30 parts by weight, preferably 5 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of the ethylene copolymer (A).
(B) If the amount of the crystalline resin is more than 30 parts by weight, the compression set is inferior, while if it is less than 3 parts by weight, the mechanical strength becomes low. (B) By the addition of the crystalline resin, the viscosity at the time of processing decreases, and the amount of the filler and the like can be increased.

The (C) amorphous resin used in the present invention preferably has a glass transition point (Tg) measured by DSC in the range of 70 to 130 ° C, more preferably 90 to 120 ° C. Those in the range are used. Specifically, polystyrene, acrylonitrile-styrene copolymer, polycycloolefin, AES resin and the like can be mentioned, and preferably, polystyrene, acrylonitrile-styrene copolymer and AES resin are used. These amorphous resins (C) can be used alone or in combination of two or more. (C) The amorphous resin is used in an amount of 3 to 35 parts by weight, preferably 5 to 25 parts by weight, and more preferably 10 to 100 parts by weight of the ethylene copolymer (A).
It is used in a proportion of ２５25 parts by weight. (C) If the amount of the amorphous resin is more than 35 parts by weight, the processability is poor, while if it is less than 3 parts by weight, the mechanical strength is low.

The total amount of the crystalline resin (B) and the amorphous resin (C) is in the range of 6 to 40 parts by weight, preferably 10 to 100 parts by weight of the ethylene copolymer (A).
To 35 parts by weight, more preferably 15 to 30 parts by weight. When the (B) crystalline resin and the (C) amorphous resin are in the above range, the balance between mechanical strength and workability is preferably maintained.

Next, the filler used in the present invention will be described. As the filler, for example, SRF, FE
Carbon blacks such as F, HAF, ISAF, SAF, FT, and MT; white carbon, fine particle magnesium silicate, calcium carbonate, magnesium carbonate, clay,
And inorganic fillers such as talc. These fillers can be used alone or in combination of two or more. The amount of the filler is usually 10 to 200 parts by weight, based on 100 parts by weight of the ethylene copolymer (A).
Preferably it is 50 to 150 parts by weight.

Next, the vulcanizing agent used in the present invention will be described. Examples of the vulcanizing agents include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium, and tellurium; morpholine disulfide, alkylphenol disulfide, thiuram disulfides, and dithiocarbamate. And other sulfur-containing organic compounds. These vulcanizing agents can be used alone or in combination of two or more. The amount of the vulcanizing agent is usually 0.3 to 20 parts by weight, preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the ethylene copolymer (A).

Further, a vulcanization accelerator can be used in combination with the above vulcanizing agent. Such vulcanization accelerators include, for example, aldehyde ammonias such as hexamethylenetetramine; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, o-tolyl-piguanide; thiocarbanilide, di (o-tolyl) thiourea Thioureas such as N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, 2- (2,4- Thiazoles such as (dinitrophenyl) -mercaptobenzothiazole and (N, N'-diethylthiocarbamoylthio) benzothiazole; N-tert-butyl-2-benzothiazylsulfenamide, N, N'-dicyclohexyl- -
Sulfenamides such as benzothiazylsulfenamide, N, N'-diisopropyl-2-benzothiazylsulfenamide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide, tetraethylthiuram disulfide Thiurams such as tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide; zinc dimethylthiocarbamate;
Carbamates such as zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate, sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate and iron dimethylthiocarbamate; butyl; Xanthogenates such as zinc thioxanthogenate are exemplified. These vulcanization accelerators can be used alone or in combination of two or more. The compounding amount of the vulcanization accelerator is (A) ethylene-based copolymer 100
It is usually 0.1 to 20 parts by weight, preferably 0.2 to 15 parts by weight based on parts by weight.

[0017] In addition to the above vulcanizing agent and vulcanization accelerator, a vulcanization accelerating aid can be added as required. Examples of such vulcanization accelerators include metal oxides such as magnesium oxide, zinc white, litharge, rhododendron, and lead white, stearic acid, oleic acid, and organic acids such as zinc stearate. Particularly preferred are zinc white and stearic acid. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator is usually 0.5 to 20 parts by weight based on 100 parts by weight of the ethylene copolymer (A).

Further, a crosslinking agent may be added to the rubber composition of the present invention, if necessary. Examples of such a crosslinking agent include 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, di-tert-butyl peroxide, dicumyl peroxide,
Organic peroxides such as tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, and 1,3-bis (tert-butylperoxy-isopropyl) benzene. . These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent
(A) It is usually 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the ethylene copolymer.

In addition, a crosslinking aid can be used in combination with the crosslinking agent. Examples of such a crosslinking assistant include sulfur, sulfur compounds such as dipentamethylenethiuram tetrasulfide; ethylene di (meth) acrylate;
Polyfunctional monomers such as polyethylene di (meth) acrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, toluylene bismaleimide; p-quinone oxime, p,
Oxime compounds such as p'-benzoylquinone oxime. These crosslinking assistants can be used alone or in combination of two or more. The amount of the crosslinking aid is usually 0.5 to 20 parts by weight based on 100 parts by weight of the ethylene copolymer (A).

The foaming agents used in the present invention include, for example, inorganic foaming agents such as ammonium carbonate, sodium bicarbonate and anhydrous sodium nitrate; dinitropentamethylenetetramine, N, N'-dimethyl-N, N'-diamine. Nitrosoterephthalamide, benzenesulfonyl hydrazide,
Organic foaming agents such as p, p'-oxybis (benzenesulfonyl hydrazide), 3,3'-disulfone hydrazide diphenyl sulfone, azoisobutyronitrile, and azobisformamide. Further, together with these foaming agents, foaming assistants such as urea-based, organic acid-based, and metal salt-based may be used in combination. These foaming agents and foaming aids are
Each can be used alone or in combination of two or more. The amount of the foaming agent is appropriately determined according to the desired foaming density.
Usually, 1 to 10 parts by weight, preferably 1 to 10 parts by weight,
８8 parts by weight.

The rubber composition of the present invention may optionally contain other various additives such as a softener, a plasticizer, a lubricant, a tackifier, an antioxidant, and an ultraviolet absorber.

Here, as the softening agent used in the present invention, synthetic oils such as aromatic oils, naphthenic oils and paraffin oils which are usually used for rubber; vegetable oils such as coconut oil; alkylbenzene oils and the like. Oil and the like. Of these, process oils are preferred, and paraffin oil is particularly preferred. The above softeners can be used alone or in combination of two or more. The blending amount of the softener is (A) ethylene copolymer 1
It is usually 10 to 130 parts by weight, preferably 20 to 100 parts by weight, based on 00 parts by weight.

When the rubber composition of the present invention is used for a sponge, the total weight of the rubber composition is in the range of 200 to 450 parts by weight, based on 100 parts of the ethylene copolymer, preferably It is in the range of 230 to 340 parts by weight. If the total number of parts by weight of the rubber composition is less than the above range, processability is poor, and if it is more than the above range, compression set at low specific gravity and mechanical strength are poor.

Further, the rubber composition of the present invention contains butyl rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer as long as the object of the present invention is not impaired. One or more other rubbers such as coalesced and other types of ethylene / α-olefin / non-conjugated diene copolymers may be used in combination.

As a method for preparing the rubber composition of the present invention, for example, (A) an ethylene copolymer, (B) a crystalline resin, and (C) an amorphous resin are sufficiently melted in an extruder and blended. Or by blending (A) an ethylene-based copolymer, (B) a crystalline resin, and (C) an amorphous resin with a kneader such as a Banbury or a kneader.

In preparing the rubber composition of the present invention, a conventionally known kneading machine, extruder, vulcanizing apparatus and the like can be used. Compounding method and compounding of vulcanizing agent and / or crosslinking agent, filler, softening agent, foaming agent, etc. mixed together with (A) ethylene copolymer, (B) crystalline resin and (C) amorphous resin. As an order, for example, (A) an ethylene-based copolymer, (B) a crystalline resin, and (C) an amorphous resin are usually added to an extruder or a Banbury mixer in advance, usually at 80 to 220.
C., preferably 100-200.degree. C., blended with a filler, a softener, etc. using a Banbury mixer or the like, and then vulcanizing and / or crosslinking agent, foaming agent, etc. using a roll or the like. Is added, but the method is not limited to this. Next, vulcanization and foaming by raising the temperature by placing the rubber composition of the present invention in a mold, or using an extruder, for example, by a method provided for the production of ordinary vulcanized rubber. After vulcanizing and foaming by heating in a vulcanizing tank after molding into an arbitrary shape, a vulcanized sponge rubber can be produced. The vulcanization / foaming conditions in this case are as follows: the temperature of the vulcanization tank is in the range of 150 to 350 ° C.
The range is 5 to 30 minutes. The specific gravity of the obtained sponge rubber is usually 0.2 to 1.0 Mg / m ³ , preferably 0.1 to 1.0 Mg / m ³ .
It is about ³ to 0.55 Mg / m ³ . The rubber composition of the present invention can be suitably used for applications such as automotive weather strip applications and sponge products such as building materials.

[0027]

The embodiments of the present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these embodiments. The measurement and evaluation in Examples and Comparative Examples were performed by the following methods.

(A) α-Olefin content (mol%) It was measured by infrared absorption spectroscopy. However, the content (mol%) of the ethylene unit and the α-olefin unit in each of Examples and Comparative Examples is a value when the total amount of these units is 100 mol%. (Ii) Iodine value It was measured by an infrared absorption spectrum method. (C) Mooney viscosity (ML _{1 + 4} , 100 ° C.) Measured at 100 ° C., 1 minute of preheating, and 4 minutes of measurement in accordance with JIS K6300. (D) Melting point (Tm), glass transition temperature (Tg) Using a 910 type differential scanning calorimeter manufactured by DuPont Instruments (currently TIA Instruments),
The sample was heated to 200 ° C., then cooled to −100 ° C. at a rate of 10 ° C./min, and measured while heating at a rate of 20 ° C./min. (E) Unvulcanized rubber properties (Vm) The minimum value of Mooney viscosity was measured at 125 ° C in accordance with JIS K6300. (F) Roll workability The roll workability was determined by the following five steps. 5: The rubber band is completely adhered to the roll, and the bank rotates smoothly. 4: The rubber band sometimes separates from the roll surface from the top of the roll to the bank. 3: Between the top of the roll and the bank, the rubber band is far away from the roll surface. 2: The rubber band does not adhere well to the roll surface and hangs down. Unless the rubber band is touched, roll processing cannot be performed. 1: The rubber band hangs down without adhering to the roll surface at all, and the roll processing cannot be performed unless the rubber band is touched. (G) Tensile test A tubular sponge with a table was cut in the length direction, and a test piece was prepared by punching out the tubular portion with a No. 2 type dumbbell. 100% M100 (MPa), tensile strength T
B (MPa) and elongation at break EB (%) were measured. (H) Compression set A tube-shaped sponge with a base having a substantially perfect circular shape whose longitudinal dimension (A) was measured was compressed 50% in the longitudinal direction, heat-treated in an oven at 70 ° C for 22 hours, and then at room temperature. After standing for 30 minutes, the vertical dimension (B) was measured and determined by the following formula. Compression set (%) = 100 × (AB) /A×0.5

Example 1 (Preparation and Evaluation of Rubber Composition) Of the components shown in Table 1, EPDM [JSR Co., Ltd .;
P65L: ML _{1 + 4} , 100 ° C. = 65, ethylene content = 6
6.5 mol%, iodine value = 29], the components of the crystalline resin and the amorphous resin were kneaded for 10 minutes at a rotation speed of 45 rpm and a set temperature of 120 ° C. using a kneader having a content of 3 L
Compound (i) was obtained. Next, each of the compounds (i) except for the vulcanizing agent components from the components shown in Table 1 was subjected to a rotation speed of 80 r using a Banbury with an inner volume of 1.7 L.
The mixture was kneaded at pm and a set temperature of 120 ° C. for 210 seconds to obtain a compound (ii). Then, the remaining vulcanizing agent components shown in Table 1 were added to compound (ii), and the mixture was kept at 50 ° C.
Knead with a 0-inch roll for 5 minutes and mix (ii)
Got i). The obtained compound (iii) is placed in a tubular die with a base (tube inner diameter 9.4 mm, wall thickness 1.5 m).
m) was extruded using a 40 mm extruder equipped with a hopper temperature of 60 ° C., a cylinder temperature of 70 ° C., and a head temperature of 80 ° C. to form a tube. This molded body was vulcanized in a hot air vulcanizing bath set at 230 ° C. for 6 minutes to obtain a sponge rubber.

Various properties were evaluated using the obtained sponge rubber. Table 3 shows the evaluation results. From the results shown in Table 3, it is clear that the vulcanized product of the rubber composition has an excellent balance of compression set, mechanical strength and processing characteristics.

Examples 2 to 5 (Preparation and Evaluation of Rubber Composition) A rubber composition was prepared in the same manner as in Example 1 to obtain sponge rubber. Various properties of each sponge rubber were evaluated, and the results are shown in Table 3. In Examples 1 and 2, as compared with Comparative Examples 1 and 3, by adding polyethylene as a crystalline resin, V
m is decreased, and therefore, as shown in Example 3, the amount of the reinforcing agent can be increased, and further improvement in mechanical strength can be seen. From the results shown in Table 3, it is clear that the vulcanized product of the rubber composition has an excellent balance of compression set, mechanical strength and processing characteristics.

Comparative Example 1 (Preparation and Evaluation of Rubber Composition) Each of the components shown in Table 2 except for the vulcanizing agent was used at a rotation speed of 80 rpm and a set temperature of 130.degree. And kneaded for 210 seconds to obtain a compound (i). Next, the remaining vulcanizing agent components shown in Table 2 were added to the compound (i), and kneaded with a 10-inch roll maintained at 50 ° C for 5 minutes to obtain a compound (ii). The obtained compound (ii) was subjected to a hopper temperature of 60 using a 40 mm extruder equipped with a tubular die having a base (tube inner diameter: 9.4 mm, wall thickness: 1.5 mm).
C., a cylinder temperature of 70.degree. C., and a head temperature of 80.degree. 230
The mixture was vulcanized for 6 minutes in a hot air vulcanization tank set at ℃ to obtain a sponge rubber. Various characteristics were evaluated using the obtained sponge rubber. Table 3 shows the evaluation results. From the results shown in Table 3, it is clear that the modulus and mechanical strength are inferior.

Comparative Examples 2 and 3 (Preparation and Evaluation of Rubber Composition) A rubber composition was prepared in the same manner as in Example 1 except that the components shown in Table 2 were used, and a sponge rubber was obtained. Was. Various properties of each sponge rubber were evaluated, and the results are shown in Table 3. From the results shown in Table 3, it is clear that the rubber composition of Comparative Example 2 is inferior in compression set, and in Comparative Examples 3 and 4, the rubber composition is inferior in balance between mechanical strength and elongation and processing characteristics. .

[0034]

[Table 1]

(* 1): LDP manufactured by Nippon Polychem Co., Ltd.
E (LJ800), Tm = 106 ° C. (* 2): Nippon Polystyrene Co., Ltd., polystyrene (G120K), Tg = 99 ° C. (* 3): Technopolymer Co., Ltd., AS resin (Sunlex S10), Tg = 110 ° C (* 4): AES resin (Techno AES W220) manufactured by Techno Polymer Co., Ltd. Tg = 110 ° C (* 5): Asahi Carbon Co., Ltd., Asahi # 50HG (* 6): Idemitsu Kosan Diana Process PS-
430 (* 7): manufactured by Maruo Calcium Co., Ltd., Super S (* 8): manufactured by Sumitomo Chemical Co., Ltd., Sumilizer GM (* 9): manufactured by Schill & Seilacher, Structor WB212 (* 10): Toho Chemical ( Co., Ltd., PEG # 4000 (* 11): Ouchi Shinko Chemical Co., Ltd., Noxeller P
Z (* 12): Noxeller M, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
Z (* 13): Noxeller D, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
M (* 14): manufactured by Kawaguchi Chemical Co., Ltd., Axel TL (* 15): manufactured by Inoue Lime Industry Co., Ltd., Vesta PP (* 16): manufactured by Eiwa Kasei Kogyo Co., Ltd., neoselbon N1
000SW

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

The rubber composition of the present invention has a low specific gravity when foamed and has an excellent balance between mechanical strength and processing characteristics. Therefore, the rubber composition of the present invention can be suitably used for sponge products of automobiles and sponge products such as building materials.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme Court II (Reference) C08L 101: 00) (72) Inventor Mamoru Hasegawa 2-1-2-11 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. ) Inventor Takashi Kawada 2-11 Tsukiji 2-chome, Chuo-ku, Tokyo F-term in JSR Co., Ltd. DJ036 DJ046 EQ018 ES008 ET008 EV047 EV147 EV167 EV268 FD016 FD147 FD150 FD328 GL00 GN00 GQ01

Claims (4)

[Claims] (A) An ethylene-α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene having a molar ratio of ethylene / α-olefin (ethylene / α-olefin) of 40/60 to 93 / 7, an ethylene copolymer in which the non-conjugated polyene has an iodine value in the range of 10 to 40,
(B) Melting point (T) measured by DSC (differential scanning calorimeter)
m) a rubber composition containing a crystalline resin having a temperature of less than 140 ° C and (C) an amorphous resin, wherein the proportion of the components (A) to (C) is (A) 100% by weight of the ethylene-based copolymer. Parts by weight of (B) 3 to 30 parts by weight of the crystalline resin, (C) 3 to 35 parts by weight of the amorphous resin, and the total amount of (B) the crystalline resin and (C) the amorphous resin Is in the range of 6 to 40 parts by weight. (C) The amorphous resin has a glass transition temperature (Tg) of 70 to 1 measured by DSC (differential scanning calorimeter).
The rubber composition according to claim 1, which is at 30C. 3. The rubber composition according to claim 1, wherein 10 to 200 parts by weight of a filler and 0.3 to 20 parts by weight of a vulcanizing agent are used per 100 parts by weight of the ethylene copolymer (A). A rubber composition for a sponge, comprising 1 to 10 parts by weight of a foaming agent. 4. A weather strip formed by molding the rubber composition according to claim 1.